About seven years ago, a publishing executive named Eric Zimmerman heard a speech by Eric Corry Freed, the author of a book called Green Building & Remodeling for Dummies. Freed talked about the responsibility that business has to protect the environment, and the stories we will tell our children about what we did. "Have you ever sat in the audience and felt someone was talking just to you?" Zimmerman asks. "That was one of those moments."

Zimmerman was moved. He did a deep energy retrofit on his home in Carlisle, Massachusetts. He put solar panels on his roof. He stopped outsourcing his company's printing to China, and he helped to create an industry brand called Green Edition that sets standards for sustainability in book publishing.

It wasn't enough. About a year ago, Zimmerman, 48, left his job to start a company called TripZero that offsets the carbon emissions generated when people travel by plane, train, car or bus – at no cost to the traveler.

A lean startup – "The company is me," Zimmerman says – TripZero is tackling one of the most intractable problems in corporate sustainability: the carbon footprint of travel and tourism.

Global travel is a huge business. A billion tourists traveled the world during 2013, and the industry generated about $2.1tn in direct global contribution to GDP from business and leisure trips, according to the World Travel and Tourism Council (WTTC).

But, despite the best efforts of hotels and airlines to position themselves as green – and, yes, hotel owners, we get it that you don't want to wash the towels and sheets every day, for whatever reason – the carbon emissions of all of the big hotel chains and airlines are growing along with their business.

TripZero offsets the carbon emissions generated when people travel by plane, train, car or bus – at no cost to the traveler. Photograph: TripZero

To be sure, once hotels and airlines have invested in efficiency, they can't do much to decouple their footprint from their growth. Sharply reducing their carbon emissions will require a decarbonized electricity sector, aviation biofuels and close to net-zero energy buildings, none of which are on the immediate horizon.

In the meantime, TripZero hopes to attract eco-conscious travelers, along with NGOs and small businesses, to its internet-based booking platform.

How it works

Through a partnership with Expedia, Zimmerman has built an online travel agency with access to millions of hotel rooms at guaranteed low prices.

Those hotels pay commissions to TripZero for attracting customers. A portion of the commissions is then deployed to buy carbon offsets, for such projects as the largest native-species reforestation campaign in Chile's history, a forest protection project in Kenya, wind turbines for Indiana schools and a methane capture project on a Pennsylvania dairy farm. The offsets are certified by reputable third parties, including the Verified Carbon Standard http://www.v-c-s.org/ and the Green-e Climate Standard.

Hotels and airlines have long invited their customers to pay a few dollars extra for offsets, but these come at no cost to the traveler. "If we can make it free, then we've really got something," Zimmerman says. TripZero doesn't book air travel because the commissions aren't big enough.

Even so, it's easy to imagine how TripZero's margins can get squeezed. Its business model works well for, say, a solo traveler going from Washington to New York by train and booking a luxury hotel. The commission far exceeds the cost of offsetting the emissions. By contrast, a family of four flying from Denver to Orlando and staying in a low-cost motel generates plenty of emissions but not enough of a commission for Trip Zero to offset their footprint. In that case, Zimmerman says, TripZero will make up the difference. "We will offset 100% of the travel we say we are going to offset," he promises.

His challenge now is to attract customers. He's planning to do a lot of direct marketing and to invite his early adopters to spread the word about TripZero. Inspire your friends and change the world, the company promises.

"I have a daughter who is six," Zimmerman says, "and in 10 years I get to tell her a good story – I hope."